CN111303337B

CN111303337B - Binary polymer diesel pour point depressant and preparation method and application thereof

Info

Publication number: CN111303337B
Application number: CN202010247435.1A
Authority: CN
Inventors: 薛原; 殷素雅; 朱贤; 金东元; 韩生; 蔺华林; 李欣; 杨太顺
Original assignee: Shanghai Institute of Technology
Current assignee: Shanghai Institute of Technology
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-12-07
Anticipated expiration: 2040-03-31
Also published as: CN111303337A

Abstract

The invention relates to a binary polymer diesel pour point depressant, a preparation method and application thereof, wherein the preparation method of the diesel pour point depressant comprises the following steps: 1) adding methacrylic acid, higher alcohol and a polymerization inhibitor into a solvent, heating to 55-65 ℃ to fully dissolve, and then adding a catalyst to perform catalytic reaction; 2) adding cyclohexylamine into triethylamine, heating to 55-65 ℃, adding methacryloyl chloride, and reacting for 1-3 h; 3) adding methacrylic acid high-carbon ester and N-cyclohexyl methacrylamide into a solvent, and then adding an initiator and carrying out polymerization reaction. Compared with the prior art, the binary polymer diesel pour point depressant has a novel structure, can effectively improve the low-temperature flow property of diesel, has good effect on reducing the condensation point and the cold filter plugging point, and can reduce the condensation point by 10-18 ℃ and the cold filter plugging point by 0-9 ℃.

Description

Binary polymer diesel pour point depressant and preparation method and application thereof

Technical Field

The invention belongs to the technical field of diesel pour point depressants, and relates to an amine binary polymer diesel pour point depressant, and a preparation method and application thereof.

Background

With the rapid development of economy, diesel fueled vehicles are increasing, and the production and consumption of diesel fuel has surpassed that of gasoline worldwide and is on an increasing trend. Diesel engines are being used in increasing numbers of countries around the world. In developing countries, diesel is mainly used in trucks, and many developed countries use diesel engines for passenger vehicles. In recent years, China will vigorously develop medium and heavy trucks according to domestic conditions. The diesel oil is a complex hydrocarbon mixture, under the condition of low temperature, normal alkane can be changed into wax crystals to be separated out from the diesel oil, and with the continuous separation of the wax crystals, a three-dimensional network structure is finally formed to block a diesel engine, so that the normal use of a diesel vehicle is influenced.

At present, the addition of the diesel pour point depressant is the most effective method for solving the problem of low-temperature flow property of diesel. The diesel oil pour point depressant mainly comprises acetic acid-vinyl acetate, methacrylate-maleic anhydride, fumarate copolymers and the like. However, many types of pour point depressants for improving low-temperature fluidity of diesel oil have good pour point depressing effect, but most of them have problems of insufficient filtration depressing effect, poor general applicability, low sensitivity to different diesel oils, low degree of dispersion, unclear pour point depressing mechanism, and the like. Therefore, the development of a diesel pour point depressant to improve the low-temperature fluidity of diesel is a problem to be solved urgently.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a binary polymer diesel pour point depressant and a preparation method and application thereof. The binary polymer diesel pour point depressant has a novel structure, can effectively improve the low-temperature flow property of diesel, has a good effect on reducing the condensation point and the cold filter plugging point, and can reduce the condensation point by 10-18 ℃ and the cold filter plugging point by 0-9 ℃.

The purpose of the invention can be realized by the following technical scheme:

a preparation method of a binary polymer diesel pour point depressant comprises the following steps:

1) adding methacrylic acid, higher alcohol and a polymerization inhibitor into a solvent, heating to 55-65 ℃ to fully dissolve, then adding a catalyst and carrying out catalytic reaction to obtain methacrylic acid high-carbon ester;

2) adding cyclohexylamine into triethylamine (simultaneously used as a solvent and an acid-binding agent), heating to 55-65 ℃, adding (slowly dropwise adding) methacryloyl chloride, and reacting for 1-3h to obtain N-cyclohexyl methacrylamide;

3) adding high-carbon methacrylate and N-cyclohexyl methacrylamide into a solvent, then adding an initiator and carrying out polymerization reaction to obtain a binary polymer of the high-carbon methacrylate and the N-cyclohexyl methacrylamide, namely the binary polymer diesel pour point depressant.

The reaction equation for preparing the binary polymer diesel pour point depressant is as follows:

further, in step 1), the higher alcohol includes one or more of tetradecanol, hexadecanol or octadecanol, the polymerization inhibitor is hydroquinone, and the catalyst is p-toluenesulfonic acid.

In step 1) and step 3), the solvent is toluene.

Further, in the step 3), the initiator is benzoyl peroxide.

Further, in the step 1), the molar ratio of the methacrylic acid to the higher alcohol is (1.1-1.3):1, the mass of the catalyst is 0.7-0.9% of the total mass of the methacrylic acid and the higher alcohol, and the mass of the polymerization inhibitor is 0.5-0.7% of the total mass of the methacrylic acid and the higher alcohol; in the step 2), the mol ratio of the methacryloyl chloride to the cyclohexylamine is (1.1-1.3) to 1; in the step 3), the molar ratio of the high-carbon methacrylate to the N-cyclohexyl methacrylamide is (2.5-3.5):1, and the mass of the initiator is 0.8-1.2% of the total mass of the high-carbon methacrylate and the N-cyclohexyl methacrylamide.

Further, in the step 1), the catalytic reaction process is as follows: pre-reacting for 0.5-1.5h, then raising the temperature to 110-120 ℃, and continuing to react for 5-6 h.

Further, in the step 3), before adding the initiator, repeatedly vacuumizing and introducing nitrogen for 2-4 times, and then raising the temperature to the polymerization reaction temperature.

Further, in the step 3), the reaction temperature is 90-110 ℃ and the reaction time is 7-8h in the polymerization reaction process.

A binary polymer diesel pour point depressant is prepared by the method. The polymer contains methacrylic acid high carbon ester long chain ester and polar group.

An application of binary polymer pour point depressant for diesel oil is disclosed.

Compared with the prior art, the invention has the following characteristics:

1) the invention introduces amide and cyclohexane in acylation reaction, wherein nitrogen atom in the amide adopts sp²Hybridization, wherein a p orbit where a lone pair electron is located and a carbonyl form p-pi conjugation, and the electron cloud density in amide molecules can be averaged by the conjugation result; cyclohexane has suitable polarity and better solubility in oil products. The long-chain alkyl nonpolar group ensures that the pour point depressant has excellent dispersibility in diesel oil, and eutectic precipitation is caused by interaction with wax components, so that the growth speed of paraffin molecules in the Z-axis direction is influenced, and the low-temperature flow property of the diesel oil is effectively improved;

2) the binary polymer diesel oil pour point depressant can reduce the pressure of an oil refinery, broaden the distillation range, is suitable for various high-wax diesel oils, is combustible and easy to decompose, and does not pose a threat to the environment.

Drawings

FIG. 1 is a 1HNMR chart of a tetradecyl methacrylate-N-cyclohexylmethacrylamide polymer obtained in example 1 (wherein m and N are integers of 1 or more);

FIG. 2 is an infrared image of a tetradecyl methacrylate-N-cyclohexylmethacrylamide polymer prepared in example 1.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

The method for measuring the cold filter plugging point is carried out according to SH/T0248-2006 method for measuring the cold filter plugging point of diesel oil and civil heating oil, and the method for measuring the condensation point is carried out according to GB510-83 method for measuring the condensation point of petroleum products.

Example 1:

(1) 10.33g (0.12mol) of methacrylic acid, 21.44g (0.1mol) of tetradecanol, 0.192g of hydroquinone and 50ml of toluene are added into a three-neck flask provided with a condenser, a water separator, a thermometer and a magnetic stirring device, the temperature is raised to 60 ℃ to completely dissolve the tetradecanol in the toluene, then 0.254g of weighed p-toluenesulfonic acid catalyst is rapidly added into the three-neck flask, the temperature is raised to 110 ℃ and 120 ℃ for reaction for 5 hours, and when the water amount in the water separator is observed to be equal to the theoretical value, the system is in a light yellow transparent liquid state, and the reaction is stopped. After the reaction is finished, distilling the obtained reaction liquid under reduced pressure, removing the solvent, and then carrying out alkali washing and water washing, wherein the alkali washing is carried out by washing with a NaOH solution with the mass fraction of 5% to remove p-toluenesulfonic acid and unreacted methacrylic acid, and the alkali washing is generally carried out for 3-4 times until the liquid is alkalescent; then washing the mixture with distilled water to be neutral, and drying the mixture in vacuum at the temperature of 60 ℃ for 5 hours to obtain the tetradecyl methacrylate.

(2) 9.917g (0.1mol) of cyclohexylamine and 20ml of triethylamine are added into a three-neck flask provided with a condenser tube, a thermometer and a magnetic stirring device, and the temperature is raised to 60 ℃ to ensure that the cyclohexylamine and the triethylamine are fully contacted;

(3) 14.13g (0.05mol) of tetradecyl methacrylate, 1.67g (0.01mol) of N-cyclohexylmethacrylamide and 25ml of toluene solvent are sequentially added into a three-neck flask provided with an electric stirrer, a temperature controller, a constant pressure dropping funnel, a reflux condenser and a nitrogen inlet pipe, the temperature is raised to 50-60 ℃, reactants are completely dissolved, the three-neck flask is pumped with nitrogen for 2-3min, then the vacuum is pumped for about 1-2min, and the process is repeated for 3 times, so as to remove the air in the reaction system. When the reaction temperature reaches 105 ℃, a toluene solution (added over 30-45 min) dissolved with 0.15g of benzoyl peroxide is slowly added dropwise, and the mixture is stirred and refluxed for 8 hours. After cooling the reaction solution to room temperature, an excess of methanol was added dropwise to the reaction product to produce a white precipitate, and the supernatant was separated off and the precipitate was redissolved in toluene. Repeating the steps for 3-4 times, removing benzoyl peroxide in the system, placing the precipitate in a vacuum drying oven, and carrying out vacuum drying for 5 hours at the temperature of 50 ℃ to obtain the tetradecyl methacrylate-N-cyclohexyl methacrylamide binary polymer. GPC determined that the molecular Mw of the bipolymer was 89603g/mol, Mn was 30854g/mol, and Mw/Mn was 2.905. The nuclear magnetic characterization of the obtained product is shown in figure 1, and the infrared is shown in figure 2.

Example 2:

the difference from example 1 is that 21.44g (0.1mol) of tetradecanol, 0.254g of p-toluenesulfonic acid as catalyst were charged in step (1) instead of 24.24g of hexadecanol and 0.277g of p-toluenesulfonic acid as catalyst, 14.13g (0.05mol) of tetradecyl methacrylate, 0.15g of benzoyl peroxide were charged in step (3) instead of 15.53g (0.05mol) of hexadecyl methacrylate and 0.184g of benzoyl peroxide, and the rest is the same as in example 1.

Example 3:

the difference from example 1 was that 21.44g (0.1mol) of tetradecanol, 0.254g of p-toluenesulfonic acid as a catalyst were changed to 27.05g of octadecanol, 0.299g of p-toluenesulfonic acid as a catalyst, 14.13g (0.05mol) of tetradecyl methacrylate, 0.15g of benzoyl peroxide were changed to 16.9g (0.05mol) of octadecyl methacrylate, 0.198g of benzoyl peroxide as a catalyst in step (1), and the rest was the same as in example 1.

Example 4:

the difference from example 1 is that 14.13g (0.05mol) of tetradecyl methacrylate, 0.15g of benzoyl peroxide to 28.25g (0.1mol) of tetradecyl methacrylate, 0.299g of benzoyl peroxide, which were added in step (3), and the rest is the same as example 1.

Example 5:

the difference from example 1 is that 14.13g (0.05mol) of tetradecyl methacrylate, 0.15g of benzoyl peroxide to 42.37g (0.15mol) of tetradecyl methacrylate, 0.440g of benzoyl peroxide were added in step (3), and the rest is the same as example 1.

The application example is as follows:

the low temperature flow property test was performed on the bipolymer diesel pour point depressant prepared in examples 1-5, and the test was performed according to the method specified in the national standard GB 510-83. The operation procedure is that the sample is loaded in a test tube and cooled to the expected temperature, the test tube is inclined at 45 degrees for 1 minute to observe whether the liquid level moves, and the arithmetic mean value of two results of repeated measurement is taken as the condensation point of the sample.

Pour point depressants prepared in examples 1-5 were numbered as # 1, # 2, # 3, # 4, and # 5, respectively, and were added to diesel fuel according to different mass percentages for condensation point testing, and the pour point depressing effect is specifically shown in table 1:

TABLE 1

The Δ SP represents the reduction of the condensation point of the diesel oil after the pour point depressant is added relative to the pure diesel oil, and as can be seen from table 1, the pour point depressants 1#, 2#, 3#, 4#, and 5# can effectively reduce the condensation point of the diesel oil, while the pour point depressant 5# prepared in example 5 has the best performance, and when the addition amount is 0.5%, the Δ SP is 18 ℃.

The copolymer diesel pour point depressants prepared in examples 1-5 were subjected to a cold filter plugging point test on diesel fuel according to the method specified in national standard SH/T0248-2006. The cold filter plugging point is the highest temperature at which the volume of liquid passing through the filter screen of the sample in a specified time does not exceed 20 ml. The arithmetic mean of the two results of the duplicate measurements was taken as the cold filter plugging point of the sample.

The pour point depressants prepared in examples 1-5 were respectively numbered as # 1, # 2, # 3, # 4 and # 5, and were added to diesel oil according to different mass percentages for cold filter plugging point tests, and the effect of reducing the cold filter plugging point is shown in table 2:

TABLE 2

Delta CFPP represents the reduction value of the cold filter plugging point of the diesel oil after the pour point depressant is added relative to the pure diesel oil, and the table 2 can show that the pour point depressants 1#, 2#, 3#, 4# and 5# can improve the cold filter plugging point of the diesel oil to a certain extent,

the pour point depressant prepared in example 5 showed good effect in lowering the cold filter plugging point, Δ CFPP of 9 ℃ when added at 0.5%.

In conclusion, based on the characteristic of molecular structure diversity of the PMA diesel pour point depressant, the invention specifically and deeply researches the structure-activity relationship and the broad spectrum, thereby driving a new trend of the development of the diesel pour point depressant and widening a new idea of the diesel pour point depressant research. The binary polymer diesel oil pour point depressant can respectively reduce the condensation point and the cold filter plugging point of the diesel oil by 10-18 ℃ and 0-9 ℃.

Example 6:

a binary polymer diesel pour point depressant is prepared by the following steps:

1) adding methacrylic acid, higher alcohol and a polymerization inhibitor into a solvent, heating to 55 ℃ to fully dissolve, then adding a catalyst and carrying out catalytic reaction: pre-reacting for 1.5h, then raising the temperature to 110 ℃, and continuing to react for 6h to obtain methacrylic acid high-carbon ester;

2) adding cyclohexylamine into triethylamine, heating to 55 ℃, adding methacryloyl chloride, and reacting for 3h to obtain N-cyclohexyl methacrylamide;

3) adding high-carbon methacrylate and N-cyclohexyl methacrylamide into a solvent, repeatedly vacuumizing and introducing nitrogen for 2 times, raising the temperature to the polymerization reaction temperature, adding an initiator and carrying out polymerization reaction at the reaction temperature of 110 ℃ for 7 hours to obtain the high-carbon methacrylate-N-cyclohexyl methacrylamide biopolymer, namely the biopolymer diesel pour point depressant.

In the step 1), the higher alcohol is tetradecanol, the polymerization inhibitor is hydroquinone, and the catalyst is p-toluenesulfonic acid. In the step 1) and the step 3), the solvent is toluene. In the step 3), the initiator is benzoyl peroxide.

In the step 1), the molar ratio of the methacrylic acid to the higher alcohol is 1.3:1, the mass of the catalyst is 0.7 percent of the total mass of the methacrylic acid and the higher alcohol, and the mass of the polymerization inhibitor is 0.7 percent of the total mass of the methacrylic acid and the higher alcohol; in the step 2), the molar ratio of the methacryloyl chloride to the cyclohexylamine is 1.1: 1; in the step 3), the molar ratio of the high-carbon methacrylate to the N-cyclohexyl methacrylamide is 3.5:1, and the mass of the initiator is 0.8 percent of the total mass of the high-carbon methacrylate and the N-cyclohexyl methacrylamide.

Example 7:

1) adding methacrylic acid, higher alcohol and a polymerization inhibitor into a solvent, heating to 65 ℃ to fully dissolve, then adding a catalyst and carrying out catalytic reaction: pre-reacting for 0.5h, then raising the temperature to 120 ℃, and continuing to react for 5h to obtain methacrylic acid high-carbon ester;

2) adding cyclohexylamine into triethylamine, heating to 65 ℃, adding methacryloyl chloride, and reacting for 1h to obtain N-cyclohexyl methacrylamide;

3) adding high-carbon methacrylate and N-cyclohexyl methacrylamide into a solvent, repeatedly vacuumizing and introducing nitrogen for 4 times, raising the temperature to the polymerization reaction temperature, adding an initiator and carrying out polymerization reaction at the reaction temperature of 90 ℃ for 8 hours to obtain the high-carbon methacrylate-N-cyclohexyl methacrylamide binary polymer, namely the binary polymer diesel pour point depressant.

Wherein in the step 1), the higher alcohol comprises tetradecanol and octadecanol, the polymerization inhibitor is hydroquinone, and the catalyst is p-toluenesulfonic acid. In the step 1) and the step 3), the solvent is toluene. In the step 3), the initiator is benzoyl peroxide.

In the step 1), the molar ratio of the methacrylic acid to the higher alcohol is 1.1:1, the mass of the catalyst is 0.9 percent of the total mass of the methacrylic acid and the higher alcohol, and the mass of the polymerization inhibitor is 0.5 percent of the total mass of the methacrylic acid and the higher alcohol; in the step 2), the molar ratio of the methacryloyl chloride to the cyclohexylamine is 1.3: 1; in the step 3), the molar ratio of the high-carbon methacrylate to the N-cyclohexyl methacrylamide is 2.5:1, and the mass of the initiator is 1.2% of the total mass of the high-carbon methacrylate and the N-cyclohexyl methacrylamide.

Example 8:

1) adding methacrylic acid, higher alcohol and a polymerization inhibitor into a solvent, heating to 60 ℃ to fully dissolve, then adding a catalyst and carrying out catalytic reaction: pre-reacting for 1h, then raising the temperature to 115 ℃, and continuing to react for 5.5h to obtain methacrylic acid high-carbon ester;

2) adding cyclohexylamine into triethylamine, heating to 60 ℃, adding methacryloyl chloride, and reacting for 2h to obtain N-cyclohexyl methacrylamide;

3) adding high-carbon methacrylate and N-cyclohexyl methacrylamide into a solvent, repeatedly vacuumizing and introducing nitrogen for 3 times, raising the temperature to the polymerization reaction temperature, adding an initiator and carrying out polymerization reaction at the reaction temperature of 100 ℃ for 7.5 hours to obtain the high-carbon methacrylate-N-cyclohexyl methacrylamide binary polymer, namely the binary polymer diesel pour point depressant.

In the step 1), the higher alcohol comprises hexadecanol and octadecanol, the polymerization inhibitor is hydroquinone, and the catalyst is p-toluenesulfonic acid. In the step 1) and the step 3), the solvent is toluene. In the step 3), the initiator is benzoyl peroxide.

In the step 1), the molar ratio of the methacrylic acid to the higher alcohol is 1.2:1, the mass of the catalyst is 0.8 percent of the total mass of the methacrylic acid and the higher alcohol, and the mass of the polymerization inhibitor is 0.6 percent of the total mass of the methacrylic acid and the higher alcohol; in the step 2), the molar ratio of the methacryloyl chloride to the cyclohexylamine is 1.2: 1; in the step 3), the molar ratio of the high-carbon methacrylate to the N-cyclohexyl methacrylamide is 3:1, and the mass of the initiator is 1% of the total mass of the high-carbon methacrylate and the N-cyclohexyl methacrylamide.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. A preparation method of a binary polymer diesel pour point depressant is characterized by comprising the following steps:

2) adding cyclohexylamine into triethylamine, heating to 55-65 ℃, adding methacryloyl chloride, and reacting for 1-3h to obtain N-cyclohexyl methacrylamide;

3) adding high-carbon methacrylate and N-cyclohexyl methacrylamide into a solvent, then adding an initiator and carrying out polymerization reaction to obtain a binary polymer of the high-carbon methacrylate-N-cyclohexyl methacrylamide, namely the binary polymer diesel pour point depressant;

in step 1), the higher alcohol comprises one or more of tetradecanol, hexadecanol or octadecanol.

2. The method for preparing the binary polymer diesel oil pour point depressant according to claim 1, wherein in the step 1), the polymerization inhibitor is hydroquinone, and the catalyst is p-toluenesulfonic acid.

3. The method for preparing the binary polymer diesel oil pour point depressant according to claim 1, wherein in the step 1) and the step 3), the solvent is toluene.

4. The method for preparing the binary polymer diesel oil pour point depressant according to claim 1, wherein in the step 3), the initiator is benzoyl peroxide.

5. The method for preparing the biopolymer diesel pour point depressant according to claim 1, wherein in the step 1), the molar ratio of the methacrylic acid to the higher alcohol is (1.1-1.3):1, the mass of the catalyst is 0.7-0.9% of the total mass of the methacrylic acid and the higher alcohol, and the mass of the polymerization inhibitor is 0.5-0.7% of the total mass of the methacrylic acid and the higher alcohol; in the step 2), the mol ratio of the methacryloyl chloride to the cyclohexylamine is (1.1-1.3) to 1; in the step 3), the molar ratio of the high-carbon methacrylate to the N-cyclohexyl methacrylamide is (2.5-3.5):1, and the mass of the initiator is 0.8-1.2% of the total mass of the high-carbon methacrylate and the N-cyclohexyl methacrylamide.

6. The method for preparing the binary polymer diesel pour point depressant according to claim 1, wherein in the step 1), the catalytic reaction process is as follows: pre-reacting for 0.5-1.5h, then raising the temperature to 110-120 ℃, and continuing to react for 5-6 h.

7. The method for preparing a biopolymer diesel pour point depressant according to claim 1, wherein in the step 3), before adding the initiator, the vacuum pumping and nitrogen introducing are repeated for 2-4 times, and then the temperature is raised to the polymerization reaction temperature.

8. The method for preparing the binary polymer diesel pour point depressant according to claim 1, wherein in the step 3), the reaction temperature is 90-110 ℃ and the reaction time is 7-8h in the polymerization reaction process.

9. A binary polymer diesel pour point depressant, characterized in that it is prepared by the process according to any one of claims 1 to 8.

10. Use of the binary polymer diesel pour point depressant of claim 9 in diesel fuel.